The top seeds, Hikaru Nakamura and Wesley So, regained their momentum today at the U.S. Championship, and occupy the two top places after five rounds, entering the first rest day.

Nakamura essayed the Dragon against Daniel Naroditsky, and went for a surprising ...Rxc3 sacrifice. That kind of sac isn't so surprising, but as Nakamura's version involved a queen trade and didn't include the usual compensating pawn it was riskier than usual. The computer wasn't impressed by the sac, but then humans aren't computers. Naroditsky didn't maintain an advantage for very long, and when he decided to return the exchange in hopes of achieving a safe position he must have miscalculated something. 28.e5 was pretty much a blunder, and while it's hard to believe Naroditsky could have played it intending to follow up with 29.Bxe5, not seeing 29...Bh6 until it was too late, it's also hard to see what he thought he'd have after 29.Rxe5. Anyway, returning the exchange only exacerbated White's problems, and a flurry of tactics soon forced Naroditsky's resignation.

So also won, defeating Timur Gareev on the white side of a Fort Knox French, with Gareev offering a funny twist with 9...h5. That didn't work out too badly, and Gareev was still only slightly worse by his 20th move. Unfortunately, the plan he chose with 20...Qb8 followed by 21...e5 wasn't so good, and while So didn't play perfectly he obtained the upper hand and never released it.

So thereby reached 3.5/5, half a point less than Nakamura. With a draw, Ray Robson would tie with So, while a win would keep him in a tie for first. Instead, he lost to Gata Kamsky, leaving both players in a tie for third place. Robson outthought himself in the opening, and chose 2...d5 rather than his usual 2...g6, aiming for the Gruenfeld. His reasoning was that Kamsky always avoids mainstream theory, opting instead for lines like the London System. Robson felt that 2...d5 would be better there, only to be surprised when Kamsky played 3.c4 and headed for "normal" theory. Robson managed to keep a decent position until around move 30 or so, but that forced him to burn a lot of time. As the time control drew near and time pressure increased, Robson couldn't keep up with Kamsky's level of play, and the veteran obtained his first win of the tournament.

The tie for third has a third player, Kayden Troff, who was unbelievably lucky against Conrad Holt, who is apparently one of his customers. Troff had a 4-0 score against Holt coming into the game, but he was totally outplayed in the opening and losing by move 13. Holt had his first chance to put Troff away on move 16 with 16.Qa3!, taking e3 away from Black's queen and preparing Bc7. Instead, he played 16.Bc7, which let Troff fight on with 16...Qe3! 19.Be6 was another error (19.Qc2!), after which the game was equal. It was only a few moves later that Holt again enjoyed a winning advantage, and he maintained it to and past the time control on move 40 as well. All Holt needed was to keep alert and make a few more accurate moves, and his two extra pawns and the terrible Black king would give him the full point.

On move 43, Holt could have played 43.Kf3, 43.Kh1 or even the taunting moves 43.Kg1 and 43.Kf2. Instead, thinking to end the game by stopping the checks, he played 43.Kh3??? This succeeded in both aims: it did end the game, and it did stop the checks. Unfortunately for him, the way the game ended wasn't what he had in mind. Troff played 43...g5!, threatening 44...Qh6#, and to White's misfortune and Black's incredible good luck, there was no way for White to stop the mate that didn't walk into some fork or other. If White played 44.g4, Black would have 44...Qh6+ 45.Kg3 Nf1+, forking the king and queen. If instead 44.Qd6+, then 44...Qxd6 45.Rxd6 g4+ 46.Kh4 and then 46...Nf5+ picks up the rook on the fork. Holt tried 44.Rd6, but once again it was time for a fork: 44...g4+ 45.Kh4 Nf5+. Holt played three more moves and resigned in understandable disgust.

The other two games (Akobian-Onischuk and Shankland-Sevian) were drawn, so let's turn to the women's championship. Here too, the key decisive game saw the winner enjoy a bit of spectacular luck on the way to victory. Irina Krush was falling prey to a great attack by Rusudan Goletiani, and had Goletiani played the naive and obvious 22...dxe5 she would have been well on the way to a victory. Instead, she got too clever by half with 22...Bxg2??, missing the neat rejoinder 23.Rh5! Qxh5 24.Qd4+!, forcing Black to either trade queens or play 24...Kg8, taking the g8 square from Black's rook. Either way, Black's attack was over and White enjoyed a non-trivial winning advantage. Krush slipped up and let Goletiani back into the game a few moves later, but near the time control Black returned the favor. Krush regained the advantage, this time for good. As a result Krush moved to 3.5/5, within half a point of Katerina Nemcova, who drew with Tatev Abrahamyan.